Apparatus for controlling the voltage in variable-speed illuminating dynamos.



E. FUCHS.

APPARATUS FOR CONTROLLING THE VOLTAGE IN VARIABLE SPEED IL-LUMINATING DYNAMOS.

APPLICATION FILED AUG- 31,1915- 1,220,971. I Patented Mar. 27, 1917.

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UNITED OFFICE.

ERNEST FUCHS, or BILLnNooUnr,--rnANcn, nssrenon. r0 LOUIS RENAULT, or BILLANcoUnr, FRANCE.

APPARATUS FOR CONTROLLING THE VOLTAGE IN VARIABLE-SPEED ILLUMINATING- DYNAMOS;

Specification of Letters Patent.

Patented Mar. 27, 1917,

Application filed August 81, 1915. Serial No. 48,353.

To all whom it may concern:

Be it known that I, ERNEST FUoHs, citizen of the French Republic, residing at Billancourt, Department of the Seine, in France, have invented certain new and useful Improvements in Apparatus for Controlling the Voltage in Variable-SpeedIlluminating- Dynamos; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to improvements in apparatus for controlling the voltage'mvariable speed illuminating dynamos, andlpar ticularly to improvements in the structure of the device set forth in U. S. Patent, No. 1,204,857, for apparatus for controlling the voltage in variable speed illuminating dynamos, dated November 14, 1916.

In the apparatus set forth in the above referred to patent, a controller isprovided which controls the field of the charging dynamo, so that a constant voltage'is maintained. This controller consists, broadly, of a casing which incloses an electro-magnet, an armature for said magnet which is moved in one direction by the magnet, and a spring which moves the armature in the opposite direction or away from the magnet. When the armature is moved away from the magnet, it closes a circuit through the field of the charging dynamo, but when the speed of the dynamo reaches a predetermined value, the magnet, which is controlled thereby, attracts the armature and breaks the field winding. The circuit from the field of the dynamo which passes through the controller includes the casing, which latter is provided with an opening, through which a cylindrical enlargement on the armature passes, which enlargement remains in the opening, irrespective of whether the armature is attracted by the magnet, or is held in its circuit-closing position under the influence of the spring. Thus the gap between the casing and the enlargement on the armature is invariable, and owing to this invariability, the weakening of the field depends solely upon the gap between the armature and the magnet, so that when the limits to which the armature may be moved are decreased, the attraction of the magnet increases proportionally to the square of the distances and out of proportion to the increase in the tension of the spring, as will be readily obvious. Thus, owing to the fact that the armature and its correlated parts are entirely removable from the casing and may be replaced by additional arts, as the occasion requires, the control of this interchange is rendered difficult. In view of the fact that the detailed construction of the device above re ferred to is set forth clearly and concisely in the patent specification, it is not deemed wise or expedient to now enter into a more detailed description, and I, therefore, will describe only my improvement.

The improvement consists broadly in the modification of the form of the enlargement on the armature and the opening in the casing through which it extends.

In the drawing, the figure illustrates a sectional view of the improved device, showing such parts as are necessary to an understanding of its operation.

The core 4 corresponds to the core of the magnet above referred to and described in the patent. This core is supported by a plate 6 which is in electrical communication with the field of the charging dynamo (not here shown), through a conductor 5. Supported by this plate 6 is an annular plate 7, which is insulated from the core 4 and from the plate 6 by suitable material 8, and resting upon the plate 7 is a second annular plate 9, on which is supported a plate 10, which plate is in electrical communication with the casing 2, but is insulated from the plate 9 by suitable material 9. An armature 11 is pivotally supported at one of its ends on the plate 9, but is insulated therefrom by the material 9 and is normally moved away from the core 4 by a spring 15. A cap 13 is supported on the plate 10, but is insulated therefrom by suitable material 13', which cap is in electrical communication with the plate 9 and carries an adjustable contact 12 which is adapted to engage a contact 12 on an enlargement 11 which is carried by the armature 11. It is to be remembered that the plates 7 and 9 are in electrical communication, and extending from the late 7 is a conductor 14 which extends to tile field of the charging dynamo. This enlargement 11 normally extends through an opening 10 in the plate 10, and it is the formation of this enlargement and of the opening in this particular combination that constitutes the present invention. The wall of the opening 10 is inclined so that the diameter of the opening at the lower face of the plate 10 is greater than its diameter at the upper face of the plate 10. lhe outer face of the enlargement 11 is likewise inclined and the angle of inclination is equal to the angle of inclination of the wall of the opening 10, as illustrated in the drawing. The enlargement 11 may be of any suitable form, such as frusto-conical, etc., but the opening 10 must be of a similar form, so that when the gap between the armature and the magnet is decreased by the movement of the adjusting screw, the gap between the enlargement 11 of the magnet and the plate 10 is proportionately increased, and, consequently, the magnetic field is weakened.

By this construction, the limits of pressure of the adjusting screw are increased for a given tension of the spring, and the apparatus is rendered more responsive to control. This is because of the fact that the curve of attraction obtained comes nearer to thecurve of the spring tension than if a cylindrical enlargement were used on the armature, as it is in the device of the patent.

- What I claim as my invention is 1. In apparatus of the kind described, the combination with a casing having an annular plate, the wall of the opening in which inclines, which casing and plate are adapted to be included in an electrical circuit, a mag netic core, an armature for the same having an enlargement extending through the aforesaid opening, the face of the enlargement being inclined in the same direction as the wall of the opening, and means for varying the extent of the movement of the armature with relation to the core.

2. ln apparatus of the kind described, the combination with a casing having an annular plate and adapted to be included in an electrical circuit, the wall of the opening in said plate being inclined, of a magnetic core, an armature for said core pivoted above the same and having an enlargement thereon extending through the opening in the aforesaid plate, the face of said enlargement inclining to the same degree as the face of the opening, a spring for normally retracting the armature from the core, and means for varying the limit of movement of the armature away from the core whereby the gap between the wall of the plate and the face of the enlargement is varied and in such relation to the variation of the spring tension that the curve of attraction of the armature approaches the curve of the spring tension.

In testimony whereof I affix my signature, in presence of two witnesses.

ERNEST FUCHS. Witnesses:

CnAs. lP. PnEssLY, HENRI CoHUns.

Copies of this patent may be obtained. for five cents each, by addressing the Gommissioner of IBatents, Washington, D. G. 

